Methyl 3-amino-2-cyano-6-(difluoromethyl)pyridine-5-carboxylate
Methyl 3-amino-2-cyano-5-(difluoromethyl)pyridine-4-carboxylate
Methyl 6-amino-2-cyano-3-(difluoromethyl)pyridine-4-carboxylate
Methyl 2-amino-6-cyano-4-(difluoromethyl)pyridine-3-carboxylate